Similar to "dropping a duece". Its where you sit down on the toilet to have a poo , but it may take awhile, so you typically bring in work to do like a laptop or a book or magazine; and since you don't want to divuldge that you're crapping when someone calls you, you tell them that you're having a sit-down meeting instead.

When you eat dirt for the first time and leave your family to build a shack in the woods